A subsequent package process or further assembly process should be conducted to a passive device cutting from wafer to produce a passive component having a passive device set on a substrate or on a device carrier; or having at least one passive device set on a substrate or on a printed circuit board with other active devices or other passive devices. Accordingly, the passive device has to be mounted on the substrate, the device carrier or the printed circuit board during either the package process or further assembly process. There are various ways for a passive device to be mounted on. Generally, the surface mounting method is the most common way for mounting the passive device on a substrate with advantages of high processing speed and high mounting precision.
FIGS. 1A and 1B illustrate cross views of a conventional surface mooting process to form a passive component. First regarding to FIG. 1A, a steel plate 14 having a plurality of opening 16 is formed on a substrate 10, wherein each opening 16 associates with a pad 12 set on the substrate 10 and exposes the pad 12 there from. A printing process is conducted to deposit solder 18 on the exposed pads 12. The steel plate 14 subsequently is removed. After the steel plate 14 is removed, a passive device 20 is located on the steel plate 14, and the power contact and the grounding contact of the passive device 20 are electrically connect to the pads 12 respectively. A solder reflow process is then conducted on the pads 12 to fix the passive device 20 on the substrate 10 by the solder deposited on the pads 12 (shown on FIG. 1B).
However, the reflow step of the prior passive devices surface mounting process may defeat the solder contact 19 by the melted solder 18 during the solder reflow process. For example, the melted solder 18 may flow or spill on to undesirable portions of the substrate 10 to cause the electrical contact between the substrate 10 and the passive device 20 failure, consequently to cause the end product invalid.
There is therefore a need to develop an improved surface mounting method to mount a passive device onto a substrate and to avoid the prior problems due to the melted solder during the reflow process.